606 
Tests  for  Albumin  in  Urine. 
f  Am.  Jour.  PLiArm 
■\        Dec..  1S*6. 
mercuric  iodide  solution.  The  mixture  of  picric  acid  aud  urine  should 
,be  boiled.  Artificial  peptones  are  thrown  down  by  this  test  in  the 
cold,  but  disappear  upon  boiling,  and  reappear  as  a  cloud  on  cooling. 
The  picric  acid  solution  should  be  dropped  into  the  tube  of  urine,  held 
vertically,  in  such  a  way  that  each  drop  falls  upon  the  centre  of  the 
surface  of  the  urine,  so  as  to  obtain  differentiation  by  the  production 
of  a  film  around  it,  if  albumin  be  present.  This  cannot  be  managed 
if  the  solution  be  poured  down  the  side  of  the  tube,  as  the  picric  acid 
solution  is  of  low  specific  gravity,  and  highly  diffusible.  This  gives 
a  precipitate,  not  necessarily  albumin,  in  the  urine  of  persons  taking 
quinine.  The  precipitate  is  distinguished  by  its  being  soluble  on  boil- 
ing, to  reappear  in  a  crystalline  form  on  cooling ;  whilst  it  gives  the 
quinine  reaction  with  chlorine  water.  This  test  also  precipitates  uric 
acid  in  the  cold ;  but  this  cloud  disappears  under  heat. 
4.  Robert's  brine-test  is  stated  to  be  sensitive,  and  very  trustworth v. 
though  not  quite  so  delicate  as  the  other  tests.  It  does  not  precipitate 
peptones  or  quinine ;  and  it  is  said  to  allow  the  discrimination  of  mu- 
cus from  albumin,  the  cloud  of  the  former  being  super-imposed  upon 
the  albuminous  cloud. 
5.  Picric  acid  brine  can  be  used  after  Heller's  method,  which  is 
not  possible  with  picric  acid  solution  alone ;  owing  to  its  specific 
gravity,  it  gives  good  results. 
6.  The  solution  of  potassio-mercuric-iodide,  with  addition  of  acetic- 
acid,  is  the  most  delicate  test  in  the  list, 
7.  Nitric  acid,  used  by  Heller's  method,  and  added  cautiously,  in 
a  somewhat  diluted  state,  to  urine  just  boiled,  is  declared  to  be  a  test 
of  great  delicacy,  and  to  be  liable  to  fewer  fallacies  than  the  other  tests 
considered.    The  drawback  to  this  test  is  its  difficulty  of  portability. 
'  8.  Acetic  acid,  added  so  as  to  ensure  a  decided  acid  reaction  to  urine 
just  before,  or  immediately  after  boiling,  is  a  delicate  test. 
The  report  states  of  mucin,  that  it  is  precipitated  by  most  of  the 
re-agents  which  precipitate  albumin.  The  distinction  of  the  two  clouds, 
when  formed  by  Robert's  brine  test,  has  been  already  noticed ;  the  same 
kind  of  indication  is  given  with  nitric  acid,  in  Heller's  method.  With 
regard  to  the  other  tests,  mucin  cloudiness  thereby  obtained  shows  less 
ready  sedimentation  than  albumin  cloudiness,  and  exhibits  a  marked 
mobile  satiny  appearance  of  the  precipitate  when  shaken  in  a  good 
light. 
In  some  urines,  the  potassio- mercuric  iodide  and  picric  acid  tests 
